
package t4j.generics;


public class LinkedStack<T> {

	private static class Node<U>{
		U item;
		
		Node<U> next;
		
		Node(){ item = null; next = null;}
		
		Node(U item,Node<U> next){
			this.item = item;
			this.next = next;
		}
		
		boolean end(){return item == null && next == null;}
	}
	
	private Node<T> top = new Node<T>();
	
	public void push(T item){
		top = new Node<T>(item,top);
	}
	
	public T pop(){
		T result = top.item;
		
		if(!top.end())
			top = top.next;
	
		return result;
	}
	
	public static void main(String[] args) {
		LinkedStack<String> lss = new LinkedStack<String>();
		
		for(String s : "Phasers on stun!".split(" "))
			lss.push(s);
		
		String s;
		
		while( (s = lss.pop()) != null )
			System.out.println(s);
	}
}
